Thread: Flashover or Backdraft?
07-15-1999, 02:09 PM #1Paul GrimwoodFirehouse.com Guest
Flashover or Backdraft?
The fire is on the 12th floor of a 30 storey tower block - office building, appartments, it doesn't matter. You are about to gain entry to the fire compartment from the stairshaft lobby....fire is smokey and hot....2 inch attack line is charged and ready. You go through your door entry procedure, down low, mask in place, in you go! Then, six feet into the room all hell breaks loose......the fire comes heading for you....a blast of superheated air followed by a mass of flaming gases, exiting at the doorway you just entered by. What happened? A flashover?.....maybe a backdraft?
When such a fire occurs in the lower half of a tall building there is every likelihood that it was the natural stack effect that caused such an ignition of the fire gases. Backdraft?.........no! Flashover?.....no! As the door to the compartment was opened a negative pressure track was opened - compartment to lobby to stair or lift shaft. This effect may cause the compartment windows, already weakened by the heat, to collapse inwards....increasing the stack flows. Any wind entering the windows would create a piston effect - pushing the fire towards the negative track - and AT YOU!!
At 3am - you need to be ready for this! It may only happen once!!
07-24-1999, 03:17 PM #2Truckie from MissouriFirehouse.com Guest
Good food for thought!
Keep 'em coming!
Proud Member of IAFF Local 3133!
07-25-1999, 09:43 AM #3NBFDT1Firehouse.com Guest
Call it whatever you want, the bottom line is that it is bad stuff aimed directly at you. Therefore, wear all your gear at every fire, have a charged hose line if possible, and know how to back out and escape if needed.
07-25-1999, 10:43 AM #4Paul GrimwoodFirehouse.com Guest
That's a very 'reactive' approach NBFDT1 - Would it not be better to grasp the skills of anticipation - know what might happen? Be more 'proactive' in your approach to firefighting and you may not be in a position where you have to back out in the first place. This post was based on a fire I went to where several guys were burned as the heat pushed DOWN two floors as well as extending up. We all learned to close doors behind us on stairshafts (where possible) and to be ready for such fire intensity, maybe with a wide angle spray pattern on entry for protection. Yes wear your gear, of course, but in ALL aspects of fire and rescue work - try to look at things with a PROACTIVE view and be one step ahead of events as they occur. On this forum we all have the opportunity to share experiences and learn from others - in this profession you NEVER stop learning!
07-25-1999, 12:22 PM #5DFDGREGFirehouse.com Guest
Not to sound disrespectfull but one question. How do you close a stairshaft door with a charged line going through it?
P.S. Good scenario
God bless & protect
07-25-1999, 01:41 PM #6Paul GrimwoodFirehouse.com Guest
That's not disrespectful Greg - Its a great point! If you are in a building where the standpipe is housed within a protected lobby, off the stairshaft, then you won't have a problem closing the stairshaft door. However, the building involved in our fire had no lobby protection for the standpipes and as you rightly point out - the hose prevents a complete closure of the door. This has been a common problem at many serious high-rise fires and has led to severe smoke conditions in the stairshafts. The only thing you can do in this situation is close the door as much as the hose will allow, to discourage the formation of negative air tracks.
Good point Greg!
07-25-1999, 03:55 PM #7NBFDT1Firehouse.com Guest
In theory, proactivity is by far the best approach. Of course it would be a better choice to know and understand what is about to happen in an emergency situation before it does and take the necessary steps to prevent bad things from happening. However, in the real world, we all know that firefighting is very much reactive. We react to the situations presented to us and do our best to handle each situation as efficiently as possible with the resourses we have. Maybe my thinking is way off but I think fire prevention efforts are proactive whereas once a fire is underway, our suppression activities become reactive. Again, these are only my thoughts based on my experiences and that has been that fire reacts differently based upon, building construction, size, type, occupancy (contributing to fire load), weather conditions, time burning, heat generated, firefighting tactics (ventilation, water application and flow, aggressive interior attack, defensive exterior attack) etc. As you stated, we can all keep learning from each other as long as we keep an open mind and realize that there are many different opinions and ways of accomplishing our primary mission. The bottom line, is to practice basic, proven tactics using the equipment we have at our disposal.
07-25-1999, 06:46 PM #8Paul GrimwoodFirehouse.com Guest
NBFDT1 - I have to agree on your point that, firefighter's in general are very adaptable people and must constantly endeavour to refine their capabilities in 'reacting'to the multitude of situations they face. However, (and this is another topic from my main post!)I must strongly voice my views in support of a pro-active approach in our role as firefighters.
You support proactivity in theory but 'in the real world' you suggest that 'we all know that firefighting is very much reactive.
Well, I will say that probably the majority of firefighters function under this 'reactive' philosophy. However, (and I am not criticising you my friend), some of the best firefighters I have ever worked with have constantly demonstrated an ability to be one step ahead of the fire. They have tactically placed themselves in positions to the utmost advantage of the fire & rescue operation, purely on instinct, as if they have actually known what is about to happen! This is a skill that can only be learned through experience, motivated by a strong desire to be the best.
A pro-active firefighter is one who will learn at least one thing from every incident! Now can we honestly say we all do that? Not only will he/she learn but they will remember it, and put it to good use someday.......maybe many years from now!
A pro-active firefighter will learn to 'read' every situation from 200 yards before arrival.....sometimes more. Knowing your nearest hydrants, knowing the type of construction, its hazards, your capability as a unit. Hey - I know you understand what I am saying! Maybe you ARE a pro-active firefighter and don't realise it! The fact that you read these boards demonstrates your enthusiasm.
In the post I refer to unusual hazards associated with stack effects in tall buildings. I want to share this experience because in 26 years it only happened once to me - so its not a common event. But after it did happen I was a lot more pro-active in my approach to high-rise fires. I was anticipating the effect and initiating actions in advance to mitigate the dangers. Ask the firefighters who fought fire on the 20th floor of Westvaco in New York 1980....same thing happened! Again in the 1990 fire in the Empire State building.....same thing! Hey, and way back in 1946 (I wasn't there!) the Winecoff Hotel in Atlanta - same thing! Negative air tracks into the stairshaft caused through stack effects.
The bottom line is - you say - 'practice basic, proven tactics using equipment we have at our disposal' - hey I agree! Did I say anything different? But if I could say just one thing to a young firefighter starting out - get pro-active - if you want to be the best of the best!
07-26-1999, 01:09 PM #9snake_eng313Firehouse.com Guest
Hey guys, Thanks Ive learned something from your discussion. Good points to ponder.
08-01-1999, 06:42 AM #10Paul GrimwoodFirehouse.com Guest
Just FYI on this thread -
Empire State Building Fire 1990 - Fire was on the 51st floor (halfway point up building)and firefighters mounted their attack from the interior 'fire tower' stairshaft. This was one of two stairways serving the floor, the conventional stairs were not used to mount the fire attack. The design of a fire tower separates it from occupied areas by a vestibule that creates a space through which smoke and fire gases are vented into an adjacent air shaft. This design is suited to evacuation but is a dangerous avenue of attack. Six FDNY firefighters were injured as the fire 'blow-torched' towards them with windows failing inwards due to the combined effects of exterior wind and interior air flows towards the fire tower stairs. A relatively 'small' fire involving 900 Sq.ft of office space became intolerable taking 18 Chiefs and 175 firefighters 4 hours to control it. Had the conventional stairshaft been used in this case the severity of conditions may not have been encountered as they were.
A final word on the 'Proactive' approach -
'To act rather than react, to be driven by enduring values and principles rather than by the winds of circumstance and feelings - this is what it means to be Proactive. Because who we are is not determined by what happens to us, but by HOW we choose to respond to what happens to us'.
USA Motivational Speaker/Writer
Stay safe.......stay 'proactive'!!!
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